Simplify the expression. $(3q-7)(3q+3)$
Explanation: First distribute the ${3q-7}$ onto the ${3q}$ and ${3}$ $ = {3q}({3q-7}) + {3}({3q-7})$ Then distribute the ${3q}.$ $ = ({3q} \times {3q}) + ({3q} \times {-7}) + {3}({3q-7})$ $ = 9q^{2} - 21q + {3}({3q-7})$ Then distribute the ${3}$ $ = 9q^{2} - 21q + ({3} \times {3q}) + ({3} \times {-7})$ $ = 9q^{2} - 21q + 9q - 21$ Finally, combine the $x$ terms. $ = 9q^{2} - 12q - 21$